Install Single Node Openshift on Intel® 10th gen NUC

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Posted by Mario Parra on September 27, 2021 · 15 mins read
Contributors:
Andrea Battaglia Markus Koch

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Introduction

The next guide will show how to deploy a Single Node Openshift (SNO) to a physical Intel® NUC.

Prerequisites:

Minimum prerequisites for the installation of single node openshift must be respected so I decided to provision a set of hardware components powerful enough to run services on the platform once it’s been installed from both the computational power and the resources availability perspective.

Let’s have a look at what it’s needed to install Single Node Openshift on a 10th gen Intel® NUC.

Hardware

Intel NUC model

NUC10i7FNK

Memory capacity

64.00 GiB

CPU model name

Intel® Core™ i7-10710U CPU @ 1.10GHz

CPU cores and clock speed

6 cores (12 with hyper-threaded) at 4,700 MHz

CPU architecture

x86_64

SSD Disk

Samsung SSD M.2 256GB

NUC

Single Node Openshift (SNO) 4.8+

SNO requires the following minimum host resources:

# Virtual CPU

8

Virtual RAM

32 GB

Storage

120 GB

Additional requirements:

In order to go through the installation process, the following additioal components are required:

Optional requirements

The following are optional requirements, but highly recommended:

  • Generated a ssh key to connect to the node from your computer with ssh

Example:

$ ssh-keygen -t ed25519 -N '' -f ~/.ssh/id_rsa

$ cat ~/.ssh/id_rsa.pub
ssh-rsa AAAAB3NzaC1yc[...]

The discovery ISO

Deploying Openshift clusters with a discovery ISO is a functionality in Tech-Preview.

The above taking into consideration that the fully SNO installation is a proof-of-concept without high availability or support.

The use of the discovery ISO will help us especially in this case by not working with VMs.

We will burn it to the USB memory to launch the installation process, without any interaction required until the SNO installation ends.

Create the ISO

To create the discovery ISO you need to login and access https://console.redhat.com/openshift/

Once you are there, click on the “Create cluster” button, select Datacenter.

Then under Assisted Installer, push the new Create cluster button.

img01

You’ll be asked to fill a form with the following info:

  • Set the Cluster name and Base domain.

  • Mark the checkbox to install single node OpenShift (SNO) and accept the warning message.

  • Select the OpenShift version (Tested with OpenShift 4.8+).

  • Edit pull secret (no need to).

img02

Click Next to continue to the Host discovery section:

img03

Then click on button “Generate Discovery ISO”

Select Minimal image file.

Paste your public key (check Optional requirements section)

In case you need to add a proxy configuration for your setup, this is the time to define it.

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Click on “Generate Discovery ISO” button, a temporary download link will appear

img05

Copy the field “Command to download the ISO” or download to your PC with button “Download Discovery ISO”

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Once the download of the Discovery ISO is complete, you are ready to burn it to the USB flash drive.

Burn ISO to USB flash drive

Obviously, start by connecting your USB flash drive to your computer.

Fedora / RHEL:

Let’s check the path of the device with “sudo fdisk -l”.

img07

You need to identify the path of type /dev/sdN, in my case is /dev/sda if yours takes another path, replace it in the next step.

Let’s burn the ISO to the USB with the command “sudo dd if=discovery_image_sno01.iso of=/dev/sda”

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Installation

The whole installation process is performed in several phases.

Each and every installation phase can be monitored and customized from the remote interface.

This section will guide you through the installation process and will highlight the potential issues and customization you’ll be asked to apply to the SNO configuration.

Start the installation

Plug the USB flash drive to the Intel NUC, don’t forget to connect also the ethernet cable.

You’ll also need to connect a keyboard and a monitor to perform take preliminary actions in order to make the NUC boot from the USB flash drive:

  • Power the NUC on;

  • When the NUC logo shows on the screen, Press F10 to access the boot menu;

    • If you are keen to apply persistent changes to the boot menu, press F2 instead and enter the BIOS menu;

    • Do not apply any changes to the default BIOS performance config, just set up the Boot section accordingly;

  • Select your USB flash drive from the boot menu to boot from it;

  • Return to the browser at the Host Discovery page;

  • After a short time the status of your host will turn into Ready.

The Overview page

img09

Click Next to continue to Networking section.

The Networking page

In the networking section you’ll be asked to pick up a subnet in the Available subnets section.

img10

Also you can modify the cluster and services networks, or change the default CNI from Openshift SDN to OVN-Kubernetes.

It’s also fine to leave as default.

Click on the Next button.

The Review page

In this page you can review all the info associated to your cluster.

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The Installation process page

This page gives you an overview of the overall installation process.

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The logs of the cluster and node installation can be consulted:

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Once the installation process reboots, the machine will need to boot from the disk.

In case the machine keeps booting from the USB flash drive. the installer will warn you about it:

boot from disk

Remove the USB and reboot the Host.

It will take about 30 minutes to the installation process to complete. Duting that timeframe, the process will complete the installation of the SNO on the machine and will perform an update of the current version, up to the latest fix version (e.g.: 4.8.2 → 4.8.9).

Once the installation process is complete you will obtain the kubeadmin password and the url to login to the console:

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DNS required configuration

In order to access the SNO Web Console, you need to setup the hostname resolution for the SNO running on the NUC.

Given:

XXX.XXX.XXX.XXX = your SNO IP

It’s possible to pick up one of the following options:

External DNS

Use an external DNS server or local configuration to resolve the SNO hostname.

Add the following records to your DNS server (recommended)

api.cluster_name.cluster_domain      A	XXX.XXX.XXX.XXX
*.apps.cluster_name.cluster_domain   A	XXX.XXX.XXX.XXX

Optional:

cluster_name.cluster_domain	A	XXX.XXX.XXX.XXX

Redirect DNS for subdomain cluster_name.cluster_domain to the NUC

During the installation of Single Node Openshift a fully functional DNS server with the required wildcard DNS is configured. So you can redirect all DNS queries for the subdomain cluster_name.clusterdomain to the NUC

Modern Linux Systems like RHEL or Fedora use NetworkManager for Networking configuration and use dnsmasq for local DNS caching. To setup DNS on a RHEL 8 client you can create the file /etc/NetworkManager/dnsmasq.d with the follwoing content:

server=/apps.cluster_name.cluster_domain/XXX.XXX.XXX.XXX
host-record=api.cluster_name.cluster_domain,XXX.XXX.XXX.XXX

Then power-cycle NetworkManager and you are good to go.

$ sudo systemctl NetworkManager restart

Local resolution:

Update your local /etc/hosts or /etc/resolve.conf files

XXX.XXX.XXX.XXX	api.cluster_name.cluster_domain
XXX.XXX.XXX.XXX	oauth-openshift.apps.cluster_name.cluster_domain
XXX.XXX.XXX.XXX	console-openshift-console.apps.cluster_name.cluster_domain
XXX.XXX.XXX.XXX	grafana-openshift-monitoring.apps.cluster_name.cluster_domain
XXX.XXX.XXX.XXX	thanos-querier-openshift-monitoring.apps.cluster_name.cluster_domain
XXX.XXX.XXX.XXX	prometheus-k8s-openshift-monitoring.apps.cluster_name.cluster_domain
XXX.XXX.XXX.XXX	alertmanager-main-openshift-monitoring.apps.cluster_name.cluster_domain

Optional:

XXX.XXX.XXX.XXX	cluster_name.cluster_domain

Start using SNO on Intel® NUC

Then you can access your new Single Node Openshift at the following URL:


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